I’ve mostly used LibreOffice for personal use and other cases where I don’t want to use Big Tech, but you could try OnlyOffice. I’ve also been interested in Grist, which is more like AirTable but programmed in Python and (relevant to your request) self-hostable.

Edit: Depending on your reasons for avoiding big tech, you may want to research the owner of Only Office, which was a Russian company but apparently isn’t anymore? You might want to also try CryptPad, which is based off of OnlyOffice and recommended elsewhere in the comments (which reminded me).